DURHAM — The names of those involved in a fatal collision Saturday morning on Route 4 have been released by the Durham Police Department, who continue to investigate the multi-vehicle crash jointly with state police.

Dead upon arrival of police and emergency crews was Bruce Larson, 74, of Durham , who had been operating a 2000 Buick when his vehicle and that of 22-year-old Ryan Merchant, 22, of Wakefield, Mass. struck head on.

The passenger in Merchant's 2004 Chrysler was Martin Hyppolite, 22, of Malden Mass. Both occupants of the Chrysler were treated for serious injuries with Merchant transported by Dartmouth Hitchcock Advanced Response Team (DHART) helicopter to Beth Israel-Deaconess Medical Center in Boston; and Hyppolite transported to Portsmouth Regional Hospital via McGregor Ambulance.

The status of Merchant and Hyppolite was unknown on Sunday.

The crash occurred at about 9 a.m. Saturday and emergency crews remained on scene for about five hours, keeping Route 4 closed to traffic between Madbury Road and the Route 4 on-ramp at Main Street near the University of New Hampshire.

The state Accident Reconstruction Unit also responded to the crash, considered a crime scene, as did Strafford County Attorney Tom Velardi and Deputy Attorney Tim Sullivan.On Sunday, Velardi told Foster's Daily Democrat that it is standard procedure that he may be called to an incident involving an untimely death in the county.

"On occasions, police departments do ask me to respond to the scene," he said and added that when he attends such an event, things are treated as a crime scene until officials complete their investigation.

The vehicles involved were towed to the county impound lot, he said, and this is to preserve anything that may be needed as evidence at a later date."It's just a precaution," he said.

On Saturday morning, it was reported over emergency radio communications that several people had been trapped within vehicles and required extrication.

The weigh station on Route 4 served as a landing zone for the DHART helicopter. Operations shut down Route 4 from Madbury Road to the Main Street on ramp near the University of New Hampshire.